The key to such developments are molecules which efficiently absorb light and can form a "charge separated state" –  where a positive and a negative charge are spatially separated and can potentially drive independent useful chemistry.   Recently, Dave Garner, Stephen Davies and their colleagues at the University of Nottingham have synthesised a new molecule that, upon excitation with light, produces such “separated charges” efficiently. The novel behaviour involves an organic moiety (a naphthalene-diimide group) acting as a light-absorber and electron acceptor and a molybdenum-dithiolene centre acting as the electron donor. The resultant electron-hole pair has an appreciable lifetime of 15 ns, as required for device applications.

The time-resolved infrared capability of the ULTRA facility was used to understand the initial response of these molecules to light and to investigate the dynamics of energy propagation. Together with electronic transient absorption spectroscopy, performed in Sheffield and Minsk over the broad time-span from femto to nanoseconds, these data provide a detailed description of the fundamental light-induced reactions in this novel photoactive molecule - information that will be used in future work in which the molecules are tuned for applications.